wlroots/util/matrix.c
Alexander Orzechowski 0bdcb22f66 Merge branch 'gles2-simplify-matrix' into 'master'
util/matrix: Simplify the interface

See merge request wlroots/wlroots!4975
2025-06-17 12:37:57 -04:00

133 lines
3.1 KiB
C

#include <assert.h>
#include <string.h>
#include <wayland-server-protocol.h>
#include <wlr/util/box.h>
#include "util/matrix.h"
void matrix_multiply(float mat[static 9], const float a[static 9],
const float b[static 9]) {
float product[9];
product[0] = a[0]*b[0] + a[1]*b[3] + a[2]*b[6];
product[1] = a[0]*b[1] + a[1]*b[4] + a[2]*b[7];
product[2] = a[0]*b[2] + a[1]*b[5] + a[2]*b[8];
product[3] = a[3]*b[0] + a[4]*b[3] + a[5]*b[6];
product[4] = a[3]*b[1] + a[4]*b[4] + a[5]*b[7];
product[5] = a[3]*b[2] + a[4]*b[5] + a[5]*b[8];
product[6] = a[6]*b[0] + a[7]*b[3] + a[8]*b[6];
product[7] = a[6]*b[1] + a[7]*b[4] + a[8]*b[7];
product[8] = a[6]*b[2] + a[7]*b[5] + a[8]*b[8];
memcpy(mat, product, sizeof(product));
}
static const float transforms[][9] = {
[WL_OUTPUT_TRANSFORM_NORMAL] = {
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_90] = {
0.0f, 1.0f, 0.0f,
-1.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_180] = {
-1.0f, 0.0f, 1.0f,
0.0f, -1.0f, 1.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_270] = {
0.0f, -1.0f, 1.0f,
1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED] = {
-1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED_90] = {
0.0f, 1.0f, 0.0f,
1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED_180] = {
1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 1.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED_270] = {
0.0f, -1.0f, 1.0f,
-1.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
},
};
void matrix_transform(float mat[static 9],
enum wl_output_transform transform) {
matrix_multiply(mat, mat, transforms[transform]);
}
void matrix_projection(float mat[static 9], int width, int height) {
struct wlr_fbox fbox = {
.x = -1.0f,
.y = -1.0f,
.width = 2.0f / width,
.height = 2.0f / height,
};
float trans[9];
matrix_project_fbox(trans, &fbox);
matrix_multiply(mat, trans, mat);
}
void matrix_project_fbox(float mat[static 9], const struct wlr_fbox *box) {
mat[0] = box->width;
mat[1] = 0.0f;
mat[2] = box->x;
mat[3] = 0.0f;
mat[4] = box->height;
mat[5] = box->y;
mat[6] = 0.0f;
mat[7] = 0.0f;
mat[8] = 1.0f;
}
void matrix_project_box(float mat[static 9], const struct wlr_box *box) {
struct wlr_fbox fbox = {
.x = box->x,
.y = box->y,
.width = box->width,
.height = box->height,
};
matrix_project_fbox(mat, &fbox);
}
void matrix_invert(float out[static 9], float m[static 9]) {
float a = m[0], b = m[1], c = m[2], d = m[3], e = m[4], f = m[5], g = m[6], h = m[7], i = m[8];
// See: https://en.wikipedia.org/wiki/Determinant
float det = a*e*i + b*f*g + c*d*h - c*e*g - b*d*i - a*f*h;
assert(det != 0);
float inv_det = 1 / det;
// See: https://en.wikipedia.org/wiki/Invertible_matrix#Inversion_of_3_%C3%97_3_matrices
float result[] = {
inv_det * (e*i - f*h),
inv_det * -(b*i - c*h),
inv_det * (b*f - c*e),
inv_det * -(d*i - f*g),
inv_det * (a*i - c*g),
inv_det * -(a*f - c*d),
inv_det * (d*h - e*g),
inv_det * -(a*h - b*g),
inv_det * (a*e - b*d),
};
memcpy(out, result, sizeof(result));
}